1/ Get coached. This is the fastest way to learn anything. A good coach gives you distilled knowledge.
2/ Ask experts. Those who excel in the field you want to learn about. And start your learning journey with what they recommend.
3/ Take courses. And get accountability partners. Taking a course alone is not enough. Because on your own you may not complete it and limit the value and learning you get from it. An accountability partner will increase your chances of completing it and speed up your learning.
4/ Read books. Pick good books that are either recommended by a trusted source or have good reviews for topics you want to learn. Don’t just read. Apply what you learn as you read.
5/ Teach others. This is a surprisingly fast way to learn almost anything. In the beginning, you’ll be confused. But as you learn with a focus on teaching others things will become clear.